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Mark H. wrote:I think I would use a drywall sanding screen as a flattener for such coarse stones. This one is 100 grit, but you can get them in 220 grit, too.

That's not going to work to well if at all on a 24 or 60 grit stone, you need something much more coarse. The sanding belt glued to a piece of wood sounds like the ticket, or the side walk.

_________________If at first you don't succeed, pay someone that knows what they're doing.

ken123

Post subject: Re: Very rough stone flatting?

Posted: Tue Apr 29, 2014 3:46 am

Forum Moderator

Joined: Mon Apr 23, 2012 4:45 amPosts: 1866Location: Skype k_schwartz

Well this thread probably has some of the worst information in it I've seen in a while, so let me clear it up.

DON'T use the sidewalk on these stones. Massive grit contamination of the stone and these stones would be rough on your sidewalk. BAD idea for these stones and a BAD idea in general for most any stone. Using the sidewalk on stones sucks as an idea - one of my pet peeves.

If you have a crappy diamond plate it will eat it up so don't do that. If you get a diamond plate the DMT plate will work OK - not recommended. The Atoma 140 will work for minor dishing and holds up much better. BUT the result will be that the diamond plate will flatten THROUGH the 24 or 60 grit particles. so you will get a much finer finish than the stone is capable of. You want a rough surface for these stones to do what they are intended to do.

You can flatten and properly texturize the 60 grit with the 24 grit. Works great!

The 24 grit stone dishes slowly BUT it will eventually dish. So what will work on it? It will eat a drywall screen for lunch - bad idea. Sidewalk - another bad idea (already mentioned but why not kill this idea twice ) Sanding belt glued to something - it will eat a 24 grit Blaze belt too - only a moderately bad idea.

If you want to get this stone truly flat you need two of these stones. This is true of other stone flatteners too - Nortons, Naniwas, pink ones, etc. And you can use this stone to flatten all of them because they will dish even more easily than the 24 grit Nubatama. This one is as rough as it gets for stones.

You can use some silicon carbide particles on it - the coarser the better, but it's messy. I've done it with the large Naniwa flattener. I don't use this technique anymore. If you are using finer loose grit, use a finer stone too.

THE classic way to flatten stones - long before diamond plates existed was to use three stones. Flatten A against B, B against C and C against A. This is ideal but you can get by with two stones just reversing the direction of the stones.

If you are a serious sharpener, I highly recommend these stones. For lighter work the 120 or 150 Nubatamas are fine - and easily flatten against the 24 grit stone too.

As an aside if you have a buffing wheel with very coarse compound (like 120 greaseless) and need to true your buffing wheel, stuffing the 24 grit stone on end into the wheel will rip the compound off - and generate a nice spark trail. Otherwise you just eat up your rakes. For repairing chips and tips, this is an excellent stone - either the 60 or 24 grit.

It does leave a coarse finish, so expect to clean it up with finer stones or even the 140 Atoma. Going from the 60 grit Nubatama to the 150 bamboo is very reasonable too.

Here's a video from an individual I don't often quote using the 24 grit stone for getting a very respectable edge on a knife - especially for a 24 grit stone. Given even reasonably good technique it can be used to advantage.

I have and use both the 24 and the 60 grit Nubatama stones lets address a few things here.

"Flattening" a 24 grit Nubatama on a sidewalk is an excellent way to gouge out your sidewalk , not to mention contamination (as already brought up by Ken but it's worth repeating). If you don't want to buy 3 then use an Atoma 140. Do so with light pressure under running water. It wont be a common occurrence as these are exceptionally hard stones for this level of coarseness. Using this method the stone takes awhile to "break in" again as you cut through the individual particles and this gives a result similar to the way spyderco ceramics work.

Now to using the 24 and 60 as stone flatteners I find they work quite well. I have a Kyushu Omhura that has a particularily hard spot (think harder than a Meara) while the rest of the stone is quite soft. Obviously this hard spot (whilst finer) wears much slower than the surrounding stone. In order to flatten this stone properly I have to flatten this hard spot parallel to the rest of the stone and get it below the surface of the surrounding stone , then blend in the surrounding stone when it comes time to use with a Tomo.

Before:

After:

This is abusive work that requires lots of pressure on a small area of stone. The 24 grit Nubatama just shrugs it off and works. It also works well for other abusive work such as nasty tip repairs , major chipping etc...

_________________Ken Schwartz is my crack dealer.....

Adam Marr

Post subject: Re: Very rough stone flatting?

Posted: Wed Apr 30, 2014 5:20 pm

Forum Moderator

Joined: Mon Apr 23, 2012 7:36 pmPosts: 3284

ken123 wrote:Well this thread probably has some of the worst information in it I've seen in a while, so let me clear it up.

DON'T use the sidewalk on these stones. Massive grit contamination of the stone and these stones would be rough on your sidewalk. BAD idea for these stones and a BAD idea in general for most any stone. Using the sidewalk on stones sucks as an idea - one of my pet peeves.

It would seem I ruffled Ken's feathers!!!! Hahaha!!!!

I damn well know that if I find a minute this weekend I'm SO going to flatten a stone on the sidewalk, post it to YT and provide it here.

Hehe, I appreciate the humor Yea that and sticking all your stones in one bucket so that the mud from one stone coats the other stones also drives me nuts. Taking a stone full of mud and tossing it back into the bucket where you can't even see the other stones makes me cringe like fingernails on a chalk board. Even when they do it in Japan Like going into a sushi bar and watching the 'chef' pull out a dull paring knife to slice sushi. Just have to leave.

Im guilty of keeping my stones the same tray of water. I hadnt really thought about it, but you are certainly right.

Would giving them a quick rinse under the tap before using them wash off some of the coarser particles, or would they eventually come to impregnate the stone?

ken123

Post subject: Re: Very rough stone flatting?

Posted: Sat May 03, 2014 8:44 pm

Forum Moderator

Joined: Mon Apr 23, 2012 4:45 amPosts: 1866Location: Skype k_schwartz

A quick rinse will usually NOT be enough. Relapping all six sides of the stone under clean running water until you see no trace of the other stone or stones is a good start. Really softer stones or porous stones will be harder to clean up.

Clay type stones like Kings will coat all your stuff badly. Shaptons will coat other stones not too badly but they WILL get coated badly by King type stones.

Just say a prayer to the mountain gods for forgiveness and all will be well again In the end it is only sharpening.

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